Evaporator



Feb. 18, 1941.

R. G. GUTHRIE EVAPORATOR Original Filed Jan. l5, 1935 3 Sheets-Sheet 1 yP/G. 5

mam! il lluenly: Robert G. GLLUQILQ,

Feb. 18, 1941. R G, GUTHmE a 2,232,176

EVAPORATOR Original Filed Jan. 15, 1935 3 shuts-Sheet 2 Feb. 18, 1941.R. G. GUTHRIE EVAPORATOR:

Original Filed Jan. 15, 1935 3 Shasta-Sheet I5 .ff/6.16. @l

- JUe'HOT: `Robert GGuUw,

Patented Feb. 18, 1941 y UNlTEDsTATEs PATENT OFFICE EVAPOBATOB Robert G.Guthrie, Chicago, 1li., asaignor to Chicago By-Prodncta Corporation, acorporation of Application January 15, 1835. Serial No. 1,917 RenewedDecember 30, 1938 -1 claim. (cass-12e) My invention relates in generalto the fabricajacent parts, the joints being formed by heating tion ofstructures comprisinga plurality of elethe parts to produce, in situbetween the joined f. ments joined together to form a unitary article.parts, an alloy, comprising the material of the the invention relatingmore particularly to the joined evaporator parts either alone or in com-5 fabrication of sheet metal devices, by fastening bination with anadditional alloy-forming mate- 5 the same together in a new and improvedmanrial or materials, the alloy being formed at a ner, andhaving specialreference to evaporators temperature sufllciently below the meltingpoint or boilers, particularly adapted for use in reof the elementsbeing joined to ensure that the frigerating apparatus. same remain insolid self-supporting condition l0 An important object of my presentinvention during the formation of the joint and thus pro- 10 is to seal.structural parts. particularly sheet mote the formation of a perfectseal to the end metal parts, forming hollow vessels. at temperathat abatch of evaporators produced byrmy tures considerably below the meltingpoint of the present method will contain a relatively high parts, inorder to eliminate collapse of the parts number of perfect devices and anegligible numor failure of the seal. ber of devices rejectible asleakers, bleeders, or 15 Another important objectis tosealingly securefor 'other structural faults, which develop in fittings on a sheet metalshell by heating the `joints effected by existing methods. same at atemperature considerably below the Another important object is toprovide for melting point of the materials forming the shell sealingnttings', such as inlet and outlet nttings,

2o and fitting. on evaporators and other shell-like devices by 20Another important object resides in securing integrating the parts byalloying the same torivets and similar fastening devices in and together. structural elements without heating the rivets Another importantobject resides in providing or the elements above the melting point ofthe an evaporator comprising two or more formed elements or the rivets.e sheets assembled in proper relative position and 25 Another importantobject is to provide a fassealed together to form a closed compartmentby tening comprising a plurality of initially separate simultaneouslyforming, between all of the parts parts, which may be mechanicallyjoined tosealed together to form the evaporator, an alloy` gether toperform a fastening function by incomprising at least the materials ofthe parts;

tegrating or uniting the same by heating at` a the alloy being formed,at temperatures sub- 3o temperature considerably below the meltingstantially below the melting point of said "parts point of any of theparts being joined in order whereby the entire evaporator shell may be4to form, between adjacent parts, an integral sealed, by merely placingthe parts in assembled p alloy comprising the material of both. positionin a suitable oven. n

A further object is to apply rivets. bolts. studs. Another important'object resides in provid- 35 pins, and similar fastening devices in theforeing an evaporator comprising a sheet metal shell going manner. andchanneled elements sealed on said shell by Another important object isto fasten a pluforming an alloy of the materials of the shell rality ofassembled elements together at a pluand the channeled elements attemperature 40 rality of remote points simultaneously by merelysufllciently below themelting p oint of the mate- 4o warming the parts.as by placing the assembly rial, comprising the shell. to inhibitsoftening of grees below the fusion pointof any of the clef the sameand'. consequent impairment ofjts selfments. supporting character, saidchanneled elements Another important object is to fabricate a formingducts communicating'with the interior sealed shell, such as a boilerorevaporator. comof the shell. 45 prising several co-operating shell partsby Another important object resides in providing assemblingthe parts intheir relative an evaporator comprising a plurality of' sheet positionsin the structure and then forming an metal parts sealed together to forma closed vesalloy or alloys simultaneously between all consei by heatingthe same to form seams,` betacting surfaces of the parts to be joinedmerely tween the joined parts, comprising an alloy of 50 by heating theassembly to a temperature several the materials of the parts with anadditional hundred degrees below the melting'point of any alioyformingmaterial interposed therebetween of the parts.v either in the form of'ashim or other layered A further object is to provide an evaporatorarrangementof the additional material, or by .55 having sealed jointsand/or seams between ad# plating. spraying. 0r dipping. or otherwiseapply- 65 ing a film of the additional alloy-forming material on one orboth of the joined surfaces, the alloy being formed between the parts ata temperature sufficiently below the melting point of the joined partsto inhibit softening of the same and consequent destruction of theirselfsupport ing character during the production of the jointformingalloy therebetween.

Another important object resides in providing an evaporator comprising apair of sheet metal plates sealed together at and within the confines oftheir marginal edges and conngurated to form therebetween an evaporatingspace including one or more header chambers and ducts communicatingtherewith, the sheets being sealed together by heating the same to formtherebetween an alloy of the material of the sheets with an additionalalloy-forming material interposed therebetween. the alloy being formedat a temperature sumcently below the melting point of the sheet materialto inhibit softening or distortion of the same, said joined plates beingthereafter conflgurated as by bending the same to substantially chanhneled form and having fittings including an inlet and an outlet fittingsealed thereon at appropriate positions, in the evaporator, by theformation of an alloy, between the fittings and the plates on whichmounted, in a manner similar to that employed in securing the sheetstogether, that is to say, by merely warming the parts to be joined. withan alloy-forming medium therebetween, to a temperature sufficientlybelow the melting point of the materials forming the plates and fittingsto prevent distortion of the same during the formation of the alloy.

' Another important object resides in providing an evaporator,comprising a sheet metal shell and a tubular element, sealed at itsopposite ends at spaced points in said shell and forming a channelcommunicating with the interior of the shell at said spaced points, theends cf said tubular element being sealed on the shell' by forming, at

`a. temperature substanuauy below the melting point of the materialsforming the shell and the element, an alloy material between theshelland the attached ends of said element, said alloy materialincluding the material of the shell and element.

A further object is to utilize the resilience of the shell and/or thetubular element to hold the parts in position during the formation ofthe alloy material, which seals the parts together.

Another important object resides in providing an evaporator comprisingtwo or more parts secured together to form a chamber, said parts beingheld in assembled position during the joining thereof by fasteningdevices adapted to become integrated with the shell parts during thesealing operation.

Another important object is to provide for fastening metallic elementsby means of a fastening device, such as a bolt or rivet, by heating saidfastening device and the elements, with which the same is associated, toform an alloy between the device and the associated elements whereby thefastening device becomes integral with the elements.

Another important object is to integrate a nut with its associated boltby warming the pieces after the same-have been threaded together inorder to form an alloy integral with and extending between thethreadedly connected portions of the nut and bolt whereby said partsbecome an integral unit.

ing means comprising initially separate parts adapted to beco-operatively associated and secured together by heating the same inorder to form therebetween an alloy material integral with both parts sothat the same are joined together for the perfomance of their fasteningfunction, said alloy being formed at atemperature sufliciently below themelting point of both parts to prevent softening and consequent loss ofholding power during the formation of the alloy.

Numerous other objects and advantages of the invention will be apparentfrom the following description. which, taken in connection with theaccompanying drawings, discloses preferred embodiments of the invention.

Referring to the drawings:

lFigure 1 is a perspective view of an evaporator made in accordance withthe teachings of my present invention;

Figure 2 shows formed sheet plates used in fabricating the evaporatorshown in Figure l;

Figure 3 is a sectional view illustrating the manner of securing theplates in facing relationship during the fabrication of the evaporator:

Figure 4 is a fragmentary view showing a modined form;

Figures 5 through 9 are enlarged sectional views to illustrate themanner in which the plates are Joined together; I

Figures l and ll are sectional views taken substantially along the linesII-II and Il ll in Figure 2;

Figures 12, 13. and 14 are sectional views taken substantially along thelines II-IZ, II-Il. and II-ll respectively in 'Figure 1;

Figure l is an end view of a modified form of evaporator, which may bemade in accordance with the teachings of my present invention;

lligures 16 and 1'1 are sectional views taken substantially along thelines ls-II and l'I-Il respectively in Figure l5; A

Figureiis'a sectional view taken through a modified form 'of evaporatormade in accordance with the teachings of my present invention;

'Figures i9 and 20 are sectional views taken substantially along thelines II-ll and 2.- respectively in Figure i8; and

Figures 21 and 22 are sectional views illustrating preferred forms offastening devices used in accordance with my present invention.

To illustrate my invention. I have shown on the drawings devices.comprising s plurality of Imetallic elements assembled and securedtogether to form an integrated product` )loro particularly, I` haveshown shell-like articles of various form and construction and eachadept-ed for use as an evaporator or boiler in refrigenting mtems.wherein e refrigeraiing medium in liquid condition is delivered in theevaporator and allowed to vapcrise therein in order io absorb heat fromthe walls therecfand from the surrounding atmosphere, the gaseousproducts of evaporation being withdrawn. compressed. liquefied. andreturned to the evaporator to completo the refrigerating cycle. lt willbe understood that devices of this character are necessarily of gastlghtconstruction in order to prevent escape of the refrigerating medium.whether in liquid or evaporated condition. from the evaporator and itsinlet and outlet fittings, and so I have provided improved means for anda method oi' sealing together the usually sheet metal elements or piecesforming the evaporator and also for attaching the inlet and outletnttings.

I have discovered that various normally solid materials, such as may beused in forming the evaporator and its nttings, can be dissolved to formalloys without necessarily approaching their .melting points and thusimpairing the self-supporting character of the same. I make use of thisdisooveryin order to sealingly secure together co-operating shell-likeand other eley, ments in order to form a sealed gas and liquid 10 tightchamber as well as to sealingly attach nttings on the shell-likeelements by heating the same, in order to form an alloy or alloystherebetween comprising the material of both Joined parts and therebyintegrate the parts without however subjecting them to temperatureswithin several hundred degrees of the melting points of theirconstituent material. The joined parts, thus, at no time during theformation of the joint or Yseam therebetween, are subjected totemperatures suiiiciently high enoughto expose the' parts to the dangerof softening or impairment of their self-supporting character. Theparts, however. are joined together without importing any distortionthereto and without weakening the same or the resulting joint so that,in production, evaporators, made in accordancewith my present invention,include an unusually small numberl of evaporators having imperfections,such as leaks and the like, in the-finished product.

The evaporator parts, to be joined together. are assembled in therelative positions to be occupied in the final product preferably with asuitable r alloy-forming medium interposed between the engaging parts tobe joined together. 'Ihis alloy-forming medium preferably comprises ametal capable of forming an alloy with the material of both parts to bejoined together and/or promoting the formation of an alloy of thematerials of said parts. For example, if a pair of steel evaporatorelements are to be joined, I may interpose, between contacting surfacesof said elements, an alloy-forming medium, such as zinc, tin. copper, oralloys of zinc, tin, or copper, or other suitable material having amelting point substantially below, preferably several hundred degreesbelow, the melting point of the parts to be joined and capable offorming an alloy with steel at temperatures substantially below themelting point of steel. Wherea pair of elements, comprising non-ferrousmaterial, such as copper, bronze, brass, are to be joined, I apply,between the facing surfaces, an alloyforming material, such as zinc,tin, copper, or

alloys comprising zinc, tin, and/or copper, or other suitablealloy-forming material having a melting point substantially below,preferably sevnon-ferrous element. The alloy-forming material may beapplied between the elements to beioined in any suitable or convenientfashion, for instance, as shown -in' Figure '1, the material may bearranged in the ferm of a shim i assembled between the pms a and l to bejoined, or. as showninFigures 5 and 6, the material may be sprayed.plated, or otherwiseapplied as in the form of apaste or varnishcontaining the medium to form a layer I upon either or both of thefacing parts, or the alloyforming medium may be applied to the surfacesto be joined by dipping the same in a molten bath of the medium.Wherethe material is sprayed or otherwise applied to both surfaces to bejoined, the surfaces may have diiferent materials applied thereon. Forinstance, in Figure 6, the element I may have a surface layer l of zinc,while the element vl has a surface 4lay'er of copper. Layers of zinc andtin, or of copper andtin, or in fact of any materials adapted to alloytogether and with the materials of the elements 3 and l may bebsed inthis rumen;

Where the alloy-forming material is applied in shim-like form betweenthe parts to be joined, I may, as shown in Figures 8 and 9, utilize aplurality of shims. In Figure 8, yI have shown two shims l in stackedrelationship between the parts 3 and i. These shims may be of differentmaterials, such as copper and zinc, zinc and tin, tin and copper, orvother suitable combinations depending upon the materialof the parts 3and I. In Figure 91 have shown three shims Il in stacked relationbetween the parts and I. 'I'he shims il may, of course, be of differentmaterial and any desired combination of zinc, tin, and/or.

copper, and/or other alloy-forming materials may be employed dependingupon the material of the parts land l. I prefer, however, to use a shimof copper between shims of zinc and/or tin.

By selectingthematerialsusedintheshlmsl and Il and in thelavers 1 shownin Figure il, as

well as their relative proportion, I may providethetemperatureofthepartsl anclltowithinr several hundred degreesFahrenheit of their melting points.

It is obvious, therefore, that the alloy-forming material or materials,whether a pure all'oy-forming material alone is used between the partsor whether an alloy or several metals adapted tov alloy together areassembled between the parts to be joined, should have a melting point orpoints well below. the melting temperature of the parts I and l.

'Iheasselnbledpartstobejoinedaresupported in Vtheir proper relativepositions with the alloyforming material therebetween and are warmed asby placing the same in a suitable oven/sumciently to raisethetemperature ofthe parts high enough to melt the alloy-formingmaterial lor materials therebetween, but without, however, ap-

proaching, within several hundred degrees, the melting point of theelements 3 and I being joined. The bonding material thereupon alloyswith the materials of both elements being joined and the application ofheat may be continued as'long as it is necessary tovpermit the parts tobe integrated by theformation of the alloy or alloys therebetween. ,l

As the parts become heated andthe alloyforming material becomes moltenat-the contacting surfaces of the pms vbeim; joined-1t wm ma;

mediately commence to penetrate in the material of said parts and formalloys therewith even though the material of the parts are attemperatures substantially below their melting point. After theformation of these alloys commerces, the alloy constituents, provided bythe elements being joined, will penetrate freely into the layer orlayers of bonding material and will eventually become intermingled toform a complex alloy of all of the associated materials.

It will be evident that if the masses now solidified, as by cooling theparts, the alloy thus formed would provide an integral gas and liquidtight joint between the joined parts and, al-

though the alloy-forming medium used between the parts may actually bebrought to molten condition during the formation of the joint, the factthat it is held in place by and between the parts vbeing joined withoutthe application of apprealloy, thus formed, moreover comprises aneverincreasing proportion of the material oi' the parts being joined andconsequently has an increasing solidification temperature, which willeventually result in the freezing of the alloy in situ between the partsbeing Joined at furnace temperature and without removing the assemblyfrom the furnace.

l Pickling or otherwise cleaning the parts to be joined, as Well as theuse of flux, or other reducing agency, is unnecessary although I preferto apply to the parts an aqueous solution of a suitable cleaning medium.For example, in joining copper or other nonferrous alloys with zinc as abonding medium, I may dip the parts to be joined in a preferablysuper-saturated solution of ammonium chloride, which will promote theformation of the alloy between the parts. I prefer to apply the ammoniumchloride to the parts after they have been arranged in assembledposition, ready for the alloy-forming application of heat, by simplydipping the entire assembly in a bath of the solution.

'I'he invention may be employed generally in joining any alloy-formingmaterials although it is particularly suitable for use in joiningrelatively flimsy structural parts, such as sheet metal elements,together or to other partsof more substantial character, without,however, impairing the shape or strength of the flimsy parts. In Figures1 through 4, I have shown how the invention may be applied in thefabrication of an evaporator comprising sheet metal means forming asealed chamber. The evaporator comprises a pair of plates Il and I5, oneor both of which are or may be' formed with integral offset portionsproviding depressions so that, when the plates are fitted andsecuredtogether in facing relationship, inter-connected passages and chambers,in which the refrigerant may be evaporated, are formed therebetween. To'this end, the sheet I is provided with spaced-apart header-formingdepressions l1 near its opposite end edges, and one of the sheets isprovided with a series of grooves I9, so that, when the 4sheets arefastened together, the depressions and grooves form spaced headerchambers 2| inter-connected by a plurality of parallel ducts 23. Thedepressions il and the grooves I9 are preferably formed in the sheet I5, the other sheet Il being assembled in position overlying thedepressions and grooves.

The sheet I3 also is or may be provided with depressions 25 in positionrespectively opposite the depressions I1 so that the depressions l1 and25 co-operate to form elongated, preferably cylindrical, header chambers2l. One of the sheets, and preferably the sheet Il, is or also may beformed at intervals with depressions or grooves 21 aording ducts 29 inthe finished evaporator, which ducts communicate with the ducts 22.

In order to seal the facing surfaces of the plates and thus provide agas-tight evaporation space therebetween, the parts are arranged inspaced relationship as shown in Figure 3, preferably with a layer Il ofa suitable alloy-forming material interposed between the facing surfacesof the sheets. As heretofore described, this alloyforming material maycomprise a shim. or shims,

or may be a paste or varnish or other layered arrangement of thematerial and the alloyforming material may be adhered upon the fac- -ingsurfaces of one or both of the sheets to be joined before the same arebrought into facing relationship. alloy-forming material by dipping,plating, spraying. or otherwise applying the material upon the surfaceof one or both of the elements to be joined and then assembling theelements in facing relationship as shown in Figure 3. The` sheets beingjoined, may be initially secured together to hold the same in assembledposition by inter-curling the edges of the sheets as shown at Il. Thesheets Il and I5 also may be formed separately, as shown in Figure 2, ormay be formed as an integral stamping, the pieces being joined along anadjacent edge to provide a single plate. In such a case, the sheets willbe assembled into facing relationship merely by folding the formed platealong said edge, as indicated at 25 in Figure 4 of the drawings, theremaining edges being preferably initially joined as by interfolding asindicated at I3 in Figure 3. It is not, of course, essential to fold theedges together in order to maintain the same in assembled position, butthe pieces may be secured together in any suitable fashion as by meansof rivets, or similar fastening devices or by means of temporary clamps.

The assembly may then be introduced into an oven adapted to heat thesame to a temperature slightly above the eutectic of the alloy, which itis. desired to form between the plates.. The eutectic of an alloy is thelowest melting temperature of any pomble mixture'of the materialscomprising the alloy, it being understood that the melting point ofalloys comprising constituents, miscibie with each other in anyproportion, varies with the proportions of the alloy constituent andapproaches the melting temperature of the constituent having the lowestmelting point.

I prefer to make the evaporator of met-al plates comprising steel orother ferrous material or alloys, or copper, or cuprous or nonferrousalloys, such as brass, bronze, and the like, said alloys preferablyhaving a relatively high melting temperature, and to utilize analloyforming material in the layer Il comprising zinc or tin, or analloy of the saine, or a cuprous alloy of zinc, and/or tin, and where analloy is used as a bonding material in the layer I'I, I prefer to emplgyan alloy having a relatively low melting pointwifn respect w the meltingtemperature of the material used-in the sheets being Joined Theassembly, as heretofore mentioned. is heated to a temperature slightlyabove the melt- I prefer, however. to apply the ing point of the bondingmaterial in the layer Il. This, however. may be and preferablyissubstantially, that is to say, several himdred degrees Fahrenheitbelow the melting temperature of the material forming the sheets Il andIl. Since the bonding material is held in place by and between thesheets Ii and it. the bonding material will be heated above its meltingtemperature by conduction through the plates between which the same isarranged and will eventually become fused. Immediately upon the fusionof the bonding material, the same will penetrate the facing surfaces ofthe sheets i8 and il being joined and will form alloys with thematerials of said sheets, even` though the sheets themselves are farshort of melting. 'Ihe application of heat is continued suillciently topermit the bonding material to become thoroughly alloyed with theadjacent surfaces of the sheets.

In order to form the evaporator shown in Figure l,thesealedplatesmaybebent, asin a suitable forming die, to the channelledlform shown and ilttings. including an inlet fitting ll. an outletiitting l. and a'channelled fitting plete the evaporator. These fittingsare preferably of copper or other non-ferrous. preferably cuprousalloys. such as brass or bronze, although, of course, the nttings may bemade of ferrous material or, inv fact, of arav'material capable offorming an alloy. The inlet fitting ll, through which liquid refrigerantis delivered into the evaporator. is preferably applied to deliver theformation of the ridges therein; The fitting Il 4 is provided withsurfaces 4B formed to snugly engage the surfaces of the sheet il aroundthe opening u. The fitting has a projecting threaded nipple 4l forattachment to a liquid delivery line and has an internal duct or channel4| extending through the fitting from the nipple and communicating withthe opening 43 when the fitting is in assembled position on theevaporator.` If desired. a tubeii may be with one end entering thechannel of the tting and extending thence'through the opening lt intothe depression 21. 'I'he ntting 31 is secured to the evaporator and tothe tube Il and the tube Il mayalsobeintegratedwiththematerialoftheevaporator by f thepartsinpositiom preferably with a llayer I3 of,suitable alloyforming material interposed between the cori.-`tactingsurfacesofthepartaandbywarming said parts in order to produce aJoint-forming alloy therebetween in the manner heretofore described.Suitable clamp means is or may be employed to secure. the iltting Il inplace during the formation of the alloy between the parts.

The fitting It similarly may be secured on the evaporator inpition'communicating with an opening'll, which is formed in the plate Ilduring the formation of the depression 2i. the

ntting It beingformed withacliannel'extendlngYfrorrisaidopeningIltoathreadedportionllvlforminga.nippleby-vrhichthesan'iemaybe v connected to thesuctionlineofarefrigerating apparatus. 'Iheflttingjl preferablyhssal-liseY Il adaptedto engageandbe 'sealedtothe evaporatoratapointre'mofxomtheopening lI-inorder to aalst in supporting the ntting t 5 thereon. 'I'he iltting Ilmay also be supported in position as by means of a suitable clamp during`the sealing of the same on the evaporator.

'I'he fitting Il, as heretofore mentioned, comprises a pipe extendingbetween and communicating with the spaced header portion 2i so thatgases generated in one headermay escape into the other and thence passthrough the outlet` tting I. The pipe 4i also forms a convenient handlefor carrying the evaporator. 'I'he pipe is secured at its opposite endsin outwardly illleted openings I3, which are preferably formed in theheader-forming portions 2l of the plate il during the pressing operationby which said portions 2i are formed. 'Ihe ends of the pipe 4I areformed to fit around the outwardly fllleted edges of the opening and thepipe may be mounted in place by slightly spreading the upwardlyextending walls of the evaporator, the resilience of the sheet metal,forming the evaporator walls. permitting the walls to press inwardlyupon and hold the pipe 4i in place:

A suitable bonding material may, of course, be applied in any suitablefashion between the contacting surfaces of the fllleted walls dening theopening I3 and the inner bore of the pipe 4| at the ends thereof. SinceI prefer to dip, spray, or plate the sheets I3 and i5 in order to coatthe same with a bonding material for joining the sheets together, I maydip the sheets initially in such a way as to apply the bonding materialat the surfaces of the sheet Il, on which all of the fittings aremounted, so that a single application of the bonding material to thesurfaces of the plate il will be suflicient not-only to permit the plateil to be Joined-with the plate i6 butalso to permit attachment of thettings.

on the evaporator.

In Figures 15, 16. and 17, I have shown a modliled form of'evaporatormade in accordance with the teachings of my present invention. Thisevaporator comprises a plurality of intertted and interconnected sheetmetal pieces and shows the possibility of employing the teachings of theinvention .in Joining together a multiplicity of parts simultaneously toform a complete evaporator. 'Ihe evaporator II comprises `an outer wall1I, the opposite sides of which are lformed with grooves 'I3 similar tothe grooves i9 in the Y evaporator shown in Figure l.

form a central dome portion and dependent facing side walls containingthe grooves 13. A pair of inner side walls "are assembled in positionoverlying the lower portions of the grooves 13 the upper ends of saidgrooves being exposed The outer wall member 1| is curved intermediateits ends to within the dome above the upper ends of the plates 16. 'I'helower and opposite end edges of the plates 1I may be curled about theadjacent end and side edgesof the member 'Il in a manner similar to thatshown at in Figure 3. and the upper edges of the plates Il are or may beformed with inwardly extending. 'flanges 'l'|.A A plate 'Il is assembledwith its opposite side edges resting on the flanges I1 so that the plateIt and the domed portions of the plate 'Il define an open endedevaporator space Il above the plate 1I. \v h ich space is incommunication with the upper ends of the grooves 'I8 as shown in Figure18. Theopenendsofthespaceil areclosed by plates I3 and Il havingJcontinuous peripheral flanges I'I adapted to snugly engage the plate 1land the domed portions of the plate Hat the opposite ends of theevaporator space. Evaporator inlet and outlet fittings It may beattached the fittings 31 and 39 on the evaporator shown l in Figure 1.

The evaporator 65 may also be provided with a bottom plate 93 havingedges secured to the lower edges of the dependent grooved portions ofthe plate 1I, preferably by inter-folding the same with the inter-foldedlower edges of the plates 1| and 15. The function of the bottom plate'93 is to support the lower legs of the ,evaporator in spacedrelationship and to generally strengthen the structure. The plate 93 mayalso serve as a bottom, on which objects to be cooled, may be supportedwithin the space dened between the plates 15. To this end, the plate 93may be provided with lateral and longitudnal flutes or grooves S5 and 91in order to strengthen the same. The plates 15 may be formed withinwardly extending beads 99 corresponding to the beads 21 of theevaporator shown in Figure 1, said beads serving to strengthen thestructure and also to provide for supporting objects in the spacebetween the plates 15. It should be understood, of course, that, inassembling the parts of the evaporator 65, a suitable bonding materialis appliedin any convenient manner between the contacting surfaces ofthe parts. The parts may be secured in temporary position in anysuitable fashion as by rivets or other suitable fastening means, orremovable clamps may be employed. After the parts have been assembledand secured, the assembly is warmed as by placing the same in an oven inorder to promote the formation of an alloy in situ, in the mannerheretofore described, between all of the contacting surfaces of theparts to be joined and sealed. In this manner, the entire evaporator issealed and integrated to final form simultaneously at all points duringthe interval that the assembly is heated.

In Figures 18, 19, and 20, I have shown still another form of evaporatoradapted for fabricuition in accordance with the teachings of my presentinvention. This evaporator III comprises a preferably sheet metal shelllli and channelled elements |05 connected at spaced points on the shellto form conduits extending outwardly of the shell between said spacedpoints of connection. The shell IIS forms a header and is preferablyconstructed by sealing a pair of preferably identically formed shellsections l0! together at their marginal edges to define1 a chamber orspace |01 therebetween. Each shell section preferably comprises a plateof semicylindrical configuration, the marginal edges of the plate beingformed to provide a continuous flange having all portions thereof lyingin a common flat plane, and the plates are secured together byinter-connection of their flanges. Each of the plates also is providedwith a series of outwardly lleted openings |09, said openings beingformed in spaced rows extending adjacent the opposite side edges of theplates. Each shell portion may also be formed with an opening III forthe attachment of an inlet or an outlet fitting. The channelled elementslil preferably comprise tubular pipes, all of which may be andpreferably are conngurated to the same identical shape as in a pipebending machine.

The evaporator is constructed by assembling the shell forming sectionsIll with their flanged edges in contacting relationship preferably witha layer of a suitable alloy-forming bonding medium extendingtherebetween. The bonding medium may, of course, be applied to the partsin any suitable or convenient manner, as for instance, by dipping,splayin. 0r plating the parts, by applying the bonding material as apaste or varnish, or in any other suitable or convenient manner, or byinterposlng a shim, comprising the bonding material, between the flangedportions of the shell sections. The sections also may be temporarilysecured in position as by means of clamps or other fastening devices.'Ihe shell sections are arranged preferably so that' the fittingopenings lll are located at one end of the shell |03, one opening beingin the lower portions of the shell on one side of a vertical planethrough the shell, while the other opening is in the upper portions ofthe shell on the opposite side of said vertical medial plane. An inletfitting lli, which may be similar to the fitting 31 heretoforedescribed, may be assembled on the shell in position to communicate withthe lower opening i Il and an outlet fitting IIB, which may l be similarto the fitting I! previously described,

may be assembled on the evaporator in position communicating with theupper opening l I i. The channelled elements or pipes Il! may then beassembled with their ends fitting over the nlleted portions of the shelldefining the openings Ill, the opposite ends of the pipes fitting uponfllleted portions in diametrically opposite positions on the shell, thepipes may be bent in such a way as to press upon and maintain themselvesin assembled position by their inherent resilience.

It will be noted that one'end of each pipe communicates with a shellopening in the upper portions of the shell and substantially in the samehorizontal plane with the upper or outlet fitting opening IH, while theother end of each pipe communicates with an opening in the lowerportions of the shells preferably in a common horizontal plane with thelower or outlet fitting opening lll. All of the pipes extend downwardlyof the shell from the lower opening I in which fitted, thence inwardlypast a vertical medial plane through the center of the shell and extendthence laterally beyond the shell and thence upwardly to their point ofcommunication in the uppermost openings l, 'Ihe pipes ill are relativelystagred and some project on one side of the unit while others project atthe op` posite side whereby to provide a central cooling mne Il1 andlateral zones III on each side of the central zone in order to blanketthe same. A suitable bonding medium may. of course, be interposedbetween the ends of the pipes Il! and the filleted shell portions, onwhich the same are mounted, and a bonding medium may likewise beinterposed between the fittings III, IIS, and the shell portions, onwhich the same are mounted. The nttings also may be temporarily clampedor otherwise secured in place in any suitable fashion.

The assembly may then be' heated in order to promote the formation of analloy between all of the interengaging parts to be sealed together.

the shell, pipes. and fittings being heated in the manner heretoforedescribed in connection with the forms illustrated in Figures 1 and l5.

It will be apparent that an evaporator as showninFlgure 18 maybeconnected inarefxigerating system adapted to deliver liquid refriger'antthrough the niet mung l l: to "n in the evaporator indicated by thedotted line |2I. This evaporator will enter the tubes from the endsthereof connected with the,v evaporator below the uduidjieveimaintained-1n the sneu.' |03. Evaporationv will'take place ln the tubes|05, the products of evaporation entering the shell |03 above 'theliquid level and escaping thence lthrough the outlet.|l5.fv l l:

While my invention contemplates the temporary fastening ofthe partsinassembled position Vduring vthe heating operation by which thejoint-forming alloy'ds created in situ between the parts to beconnected,andwhile the temlike character. Such devices, although applied ymerelyfor the purpose of holding the parts temporarily until -the same can besealed, may, during the lheating operation, become integrated Awith theparts being treated end consequently remain'on the finished article asan integral part of the same, in which thefastening devices may serve adecorativevpurpose: d

shank of which is assembledthroughperfora# projects from the anges andis threaded t'o receive a nut |29. The headed pin |25 and cooperatingnut |29 may .be sprayedl with or=dipped in a suitable bonding materialadapted to form an alloy with-saidparts and with the material of theflanges |21 in which the yfastening device is applied. or the parts ofthe fastening device may be formedof material capable of alloyingdirectly with the material .of the flanges. In either event, the parts,upon becoming heated,

will produce an. alloy therebetween whereby the same become integrah.

In Figure 22, the flangesl |21 are held together by means of a simplerivet comprising a shank having a preferably pre-formed head on one end.

the shank being inserted through the perforations of the partsbeingjined and having its OPPO- site end peened over as at |31. Asuitable Ibond-V for the purpose of-strengthening the structure, inwhich mounted,- or for purely decorative pur- My present inventionprovides a simple and inexpensive method? of, fabricatingassembled ,nnenmade by Joining- 'n plnniity or parte to- 2,232,176 level v orsacriicing any of its attendant'advantages, the

gether.- More particularly, the invention provides for the fabricationof shell-like devices, such Vas evaporators or boilers, forrefrigeration apparatus and permits a multiplicity of parts to be fsealed or 'seemed together in an air-tight manner bv the mereapplication of heat at temperatures several Ahundred Fahrenheit degrees'below the `melting point of the parts being joined. f The .parts,moreover, are seamed and sealed together at a. multiplicity o'f remoteplaces simultaneously and during the relatively short interval, usuallyin the neighborhood of three minutes, during which the parts beingJolnedare heated. I find that evaporators.' made in accordance with theteachings of my present invention, are able to 15 sustain pressureswithout leakage many times greater than evaporators made in accordancewith previous methods and furthermore my present invention permitsevaporators to be fabricated Y.

quickly and easily withoutunusual care and, in 2 fact, with considerablyless supervision than is necessary in making evaporators by existingmethods.

A set of evaporators, made in accordance with percentage of perfectunits than -is the case with evaporators made by existing methods, andit is v 'thought that the numerous advantages, including In Figures 2rand 22.1 have shown fastening devices used inthis manner.`l`l Theldevice shown.

in Figure .2l-comprises afheaded pin |275, the.

the simplicity, low-cost, andtheii'nproved characterof the resulting`product will provide a sub- 3 stantial advance in the particular art ofevapora,-

v tor fabrication; tions formed in sheet metal flanges '|21 to besecured together. The unheaded end of the pin It is thoughtithat theinvention and numerous of its attendant advantages will be understoodfrom the foregoing description and it is obvious 3 that numerous changesmay be made in the form,V

'construction, and arrangement of the several parts of the illustratedapparatus without departing from the spirit or scope of my inventionpreferred modes and forms herein described being merely for the purposeof illustrating the invention.

Having'thus described my invention, what I claim as new and desire tosecure by Letters 4 Patent is as follows:

An evaporator comprising al sheet metal shell havingspaced apartheader-forming portions, said portions being formed each with an openingdefined by a fillet extending outwardly, and a 5 connection between saidheader portions com prising a tubular member receiving said filletswithin its opposite ends and sealingly secured on said llets by an alloyformed in situ throughout the space between the engaging surfaces of the5 fillets and the end portions of the tubular member; said illletsbeingdisposed on said shell in of said alloy.

' ROBERT G. GUmIE.

myl present invention, will contain a much higher 2 y l CERTIFICATE 'OFCORRECTION.

Patent No. 2,252,176. February 18, 19m. ROBERT G. GUTHRIE.

It. is-he'reby, certified that-, 'error appears lin-.the printedspecification off'the above `numberedpatent: requiring correction as follows: Page l, first; linehl, aftuerassembly insert the words andsyllableI --in an oven to@ temperature severalhundred depage 5, firstcoiumn; line 60,

"fcr'-"and r'ead -ann--'; 'page lh'first column, line 5, for "commerces"read y'vccxnmex'rces-v-; angl that thesgaficlv Letters Patentshouldvberead witnthis 'correctiontherein thajttpe same may conform tothI record o`\ the case Ain the Patent office.

vSigned'aud sealed thi'sZIth'day of May, ALVD. 1914.1.

*A Henry Van `Arsdale (Seal) f n Acting Commissioner of' Patents;

' CERTIFICATE 'OF.CORRECTION.

Patent run-2,252,176. February 18, 19in. .ROBERT G. GUTHRIE.

It. is-he'reby certified that, `error appears .in-.the printedspecification of `the above qnmmoered-I paltentzA requiring correctionas follows: Page l, -first colpmj line-h1, after-Waalsemply" insert thewords and syllable --in an 'o'ven to temperature sveralrhundred depage5, first coiumn; line 60,

"fo'r`-"and r'ead "dn-5;' page M ',first column, line 5, for "commerces"read `"eom'luenlssfran@ that theslafidv Letters Patent should'be'readwith-this c or'recftion. t:hereinY tt'the s ame mary-conform to th'erecord o'i\ the case 'in the Patent office.

A Henry Vain Arsdale l(Seed.) -L A Acting Commissioner of' Patents.

